The present invention relates generally to ball valves and more specifically, to ball valves used as intake, in-line or discharge valves for fire pumps and firefighting apparatuses.
In firefighting apparatuses, ball valves are used at both the intake and discharge outlets for firefighting pumps as well as in in-line positions in the piping of a firefighting unit. Over periods of time, the seals of the ball valves tend to adhere to the ball component of the valve unit. Further, mineral deposits such as dirt or grit may deposit on the ball component. Depending upon the environment and the specific media flowing through the valve, the valves may become extremely difficult to open. Further, because the ball valves are often disposed in areas with little space, the ball valves must be provided with relatively short handles that transmit little torque to the valve. As a result, only firefighters with superior physical strength are able to open and close ball valves that have accumulated dirt and grit on the ball component.
The only way to overcome the above problem is to lubricate the valve seat or seal as well as the ball component. Unfortunately, due to space constraints on firefighting apparatuses, the ball valves may be disposed in inconvenient places or buried underneath other operating elements of the firefighting apparatus. As a result, the ball valves may be difficult to obtain access to which makes them very difficult to lubricate. Typically, the firefighting apparatus must be pulled out of service and the lubrication performed by qualified mechanics.
Another way to overcome the above sticking problem has been to utilize a plastic ball component and plastic seat elements. The plastic elements are typically fabricated from ultra-high molecular weight polyethylene which is considered self-lubricating. Unfortunately, this solution presents its own shortcomings because polyethylene is susceptible to deterioration from rust, grit and other mineral deposits that form on the ball component. Specifically, when the valve is opened and closed, the deposits on the ball component score and cut into the valve seat and/or the ball component itself thereby resulting in leakage and/or valve failure.
Another approach utilizes a soft elastomer for the seal element as opposed to the rigid polymer or high molecular weight polyethylene discussed above. Soft elastomer material is available that is resistant to tears and cuts. Further, soft elastomers can be impregnated with lubricants which further enhance their performance and operating life. However, it has been found that the use of soft elastomers still results in the sticking problem discussed above and has not reduced the amount of torque required to open or close a ball valve that has been in service for an extended period of time.
Further, another problem associated with the use of soft elastomers as seal elements is that soft elastomers often fail to provide support for the ball component of larger valves, such as valves with ball components having diameters greater than two inches. It has been found that, with the use of larger ball components, an increased amount of seal pre-load must be applied between the ball and the seal element in order to provide the support necessary for the ball component. As a result, the increased amount of seal pre-load that is required also increases the amount of torque necessary to open and close the valve. Further, the stress resulting from the increased seal pre-load can also lead to premature failure of the soft elastomer seal.
As a result, both the rigid polymer valve seats and seals and the soft elastomer seals each have their associated shortcomings. Both types of seals are susceptible to premature damage and failure. Further, once any seal of a ball valve is damaged, the valve must be repaired and, as discussed above, this often requires removing the firefighting apparatus from service. It has also been suggested to employ seal elements on both sides of the ball component; however, this further exacerbates the problem of the torque required to open and close the valve once the valve has been in use for a sufficient time to accumulate dirt, grit and other mineral deposits on the ball component.
Another problem associated with the ball valves used in firefighting apparatuses is the inflexibility of the mounting of the ball valve. Specifically, due to cramped space requirements on firefighting apparatus, it is often difficult to mount the actuator of the valve in a position where it can be utilized by firefighting personnel. One solution to this problem has been to make the actuator positioning adjustable in 90xc2x0 increments or in 45xc2x0 increments by using various adaptors between the valve body and the actuator. Further, the servicing of valves often proves difficult because the bolts required to mount the actuator on the valve are often difficult to obtain access to in the cramped environment of today""s modem firefighting apparatuses. Still further, the typical installment of such valves requires four bolts disposed on each side of the valve that are used to mount the valve between the pump and a conduit or in-line between two pieces of conduit. The use of these bolts disposed on either side of the valve add to the overall effective length of the valve which is disadvantageous due to the limited space availability on firefighting apparatuses.
Still another problem associated with current ball valves of firefighting apparatuses is specifically associated with large diameter hoses which are desirable because they provide increased water flow to the fire. As noted above, larger hose diameters require larger ball valves which, in turn, as discussed above, are prone to premature failure and leakage. Further, when larger diameter hoses are employed, they present their own hazards because they typically have lower pressure ratings than smaller hoses. This problem is exacerbated if the flow of water or firefighting material is shut off at a downstream location. The resulting increase in pressure in the hose can cause the hose to snap and fling violently.
As a result, one solution to this problem has been to locate a remote adapter containing a relief valve on the pump discharge outside of the pump housing or the panel that surrounds the pump. However, this solution creates its own problem in that the relief valve must also be located outside of the housing or panel as well. Another solution is to provide a portable unit outside the pump panel (containing a relief valve) for that line.
However, the location of the relief valve outside of the panel is dangerous because the release of exhaust water from the relief valve poses a safety hazard to firefighting personnel. Further, in the event the relief valve fails, there is no protective panel or housing between the failed relief valve and the firefighting personnel. Still further, the relief valve is exposed, thereby making it accessible to being tampered with, particularly the relief valve pressure setting. For example, an inexperienced person may reset the pressure to a level above the safety limits of the hose and/or firefighting industry standards. Still further, placement of the discharge outlet and relief valve outside of the housing panel results in the discharge outlet and relief valve extending outward beyond the body of the firetruck, which poses a significant driving hazard.
Accordingly, there is a need for an improved seat and sealing element for ball valves which will result in a reduction in the amount of torque required to operate the valves, which reduce the likelihood of premature leakage and which reduce the likelihood of premature failure of the ball valve. Further, there is a need for an improved ball valve design which provides greater flexibility in mounting the ball valve so that the actuator and the ball valve itself can be more readily accessed after installation for both operation and maintenance. Still further, there is a need for an improved system and method for lubricating ball valves of firefighting apparatuses to thereby make them more easy to use and increase their operating life span. And, there is a need for an improved ball valve and relief valve design which will enable the relief valve to be disposed within the housing or panel of the truck with the ball valve as opposed to outside of the housing or panel of the truck.
The present invention satisfies the aforenoted needs by providing an improved ball valve which comprises a valve body having two open ends in a ball disposed within the valve body. One end of the valve body comprises a seat housing. The seat housing comprises an inner surface with a recess for accommodating a seal assembly between the seat housing and the ball. The seal assembly comprises a seat member, a load bearing seal and a soft seal. The seat member comprises a cylindrical body extending along the inner surface of the seat housing. The cylindrical body comprises an inner end directed at the ball and an outer end directed away from the ball. The cylindrical body is connected to a radially outwardly extending flange which is disposed between the inner and outer ends thereof and that extends into the recess of the seat housing. The flange supports the load bearing seal and the soft seal between the flange and the ball.
In an embodiment, the load bearing seal is disposed between the soft seal and the inner end of the cylindrical body of the seat member.
In an embodiment, the soft seal comprises a nitrile rubber impregnated with polytetrafluoroethylene as a lubricant.
In an embodiment, the load bearing seal comprises polytetrafluoroethylene with a carbon graphite filler for added strength.
In an embodiment, the load bearing seal comprises an outer end that rests against the flange of the seat member and an inner end that engages the ball. Similarly, the soft seal comprises an outer end that rests against the flange and an inner end that engages the ball. The inner end of the soft seal extends laterally beyond the inner end of the load bearing seal.
In an embodiment, the inner end of the soft seal further comprises a bulbous tip.
In an embodiment, the recess of the seat housing forms an annular ledge that faces the ball. The flange of the seat member is spaced from the ledge with a sealing ring disposed therebetween.
In an embodiment, the flange of the seat member comprises an outer end connected to an outer wall that extends towards the ball. The outer wall is spaced from the inner end of the cylindrical body with the soft seal and load bearing seal trapped therebetween.
In an embodiment, the outer wall curves inwardly towards the soft seal thereby trapping the soft seal and the load bearing seal between the inner end of the cylindrical body and the outer wall.
In an embodiment, the seat housing comprises an outer surface and a passageway that provides communication between the recess and the outer surface. The valve further comprises a check-type lubrication fitting connected to the passageway at the outer surface of the seat housing. The flange of the seat member comprises an aperture that extends through the flange and provides communication between the passageway and the soft seal and the load bearing seal.
In an embodiment, the seal assembly further comprises an aperture that extends through the flange of the seat member and between the soft seal and load bearing seal. The aperture thereby provides communication between the recess and the ball.
In an embodiment, the recess of the seat housing forms an annular ledge that faces the ball. The flange of the seat member is spaced from the ledge with a sealing ring disposed therebetween. The sealing ring is disposed radially inwardly from the inner surface of the seat housing thereby providing an annular space defined by the sealing ring, the inner surface of the seat housing, the ledge and the seal located on the flange side of the seat member. The seat housing further comprises a passageway extending through the housing and providing communication between the annular space and a lubrication fitting. The seal assembly further comprises an aperture that extends through the flange and between the soft seal and the load bearing seal thereby providing communication between the annular space and the ball.
In an embodiment, the ball valve further comprises an inlet conduit and an outlet conduit that share a common axis. The inlet end of the valve body is connected to the inlet conduit with a first circular clamp and the outlet end of the valve body is connected to the outlet conduit with a second circular clamp. As a result, the ball valve may be rotated about the common axis of the inlet and outlet conduits thereby providing enhanced flexibility with respect to the position of the ball valve actuator.
In an embodiment, the valve body is connected to a bottom cover plate which includes two drain ports disposed on opposing sides of the common axis.
In an embodiment, the valve body includes drain ports disposed on opposing sides of the common axis.
In such an embodiment, the cover plate may be removably mounted to the valve body with fasteners, such as bolts or screws.
In an embodiment, the inlet and outlet ends of the valve body may further comprise circumferential flanges. Similarly, the inlet and outlet conduits may further comprise circumferential flanges. The first and second clamps being clamped around the circumferential flanges of the inlet conduit and inlet end of the valve body and the outlet conduit and outlet end of the valve body respectively.
In an embodiment, the present invention provides an improved lubrication system for the ball, valves of a firefighting apparatus or vehicle. The lubrication system of the present invention includes a pump for pumping metered amounts of lubricant. The pump is connected to at least one manifold which, in turn, is connected to at least one lubrication fitting. The lubrication fittings are connected to an outer surface of a seat housing of a ball valve as described above. Metered amounts of lubricant may thereafter be pumped through the lubrication fitting and to the soft and load bearing seals as well as to the ball component. In such an embodiment, a suitable lubricant metering system can be employed such as the Grease Jockey(copyright) system provided by Lubriquip, Inc.
In an embodiment, the lubrication pump is controlled by a controller.
In an embodiment, the lubrication pump is powered by air pressure.
In an embodiment, the lubrication pump is connected to lubrication fittings disposed on the pump itself and/or to lubrication fillings disposed on other components of the firefighting apparatus for purposes of preventative maintenance.
In an embodiment, the present invention provides an improved seal assembly for a ball valve which includes the seat member, load bearing seal and soft seal elements as described above.
In an embodiment, the present invention provides an improved configuration for a firefighting apparatus which includes a pump having a discharge outlet that is connected to the inlet end of a ball valve body. The valve body comprises an outlet end connected to an outlet conduit which passes through a housing panel. Thus, the valve body is disposed between the housing panel and the pump. The outlet conduit is also connected to a relief valve which also is disposed between the pump and the panel. Therefore, the ball valve and relief valve are disposed inside the housing panel, between said panel and said pump.
The present invention also provides an improved method of lubricating ball valves of firefighting apparatuses which comprises the step of pumping lubricant to a lubrication fitting connected to the outer surface of a seat housing of the improved ball valve assembly of the present invention as discussed above. Such an improved method can be carried out automatically using an automated system such as the Grease Jockey(copyright) system sold by Lubriquip, Inc.
It is therefore an advantage of the present invention to provide an improved seal assembly for ball valves.
Another advantage of the present invention is to provide an improved ball valve assembly.
Another advantage of the present invention is to provide improved ball valves for firefighting equipment.
Another advantage of the present invention is to provide an improved seal assembly for ball valves which combines benefits of load bearing seal elements and soft seal elements in a single seal assembly.
Another advantage of the present invention is that it provides an improved means for lubricating ball valves.
Yet another advantage of the present invention is that it provides ball valves for firefighting equipment that require less torque to open or close than that of prior art ball valves for firefighting equipment. Specifically, the load bearing seal reduces the operational torque of the valve by supporting the ball without adding additional pre-load to the seal. Further, the load bearing seal reduces the operational torque of the valve by acting as a wiper as well as a bearing for the ball. As a result, the load bearing seal decreases the drag or friction between the soft seal and the ball. Further, as the load bearing seal removes grit from the ball by acting as a wiper, also lubricates the ball surface. Thus, in addition to reducing the operational torque of the valve, the load bearing seal also extends the life of the soft seal by reducing the stresses on the soft seal. Still further, the load bearing seal acts as a secondary seal or a backup to the soft seal.
Another advantage of the present invention is that it provides an improved system for lubricating ball valves of firefighting equipment. By lubricating the ball valve, dirt and grime can be removed or washed off of the ball which extends the useful life of the seal members.
Yet another advantage of the present invention is that it provides an improved method for lubricating ball valves of firefighting equipment.
Still another advantage of the present invention is that it provides an improved ball valve whose position upon installation may be infinitely (or infinitely adjustable) rotated so as to make the actuator and serviceable elements of the ball valve more accessible.
And another advantage of the present invention is that it provides an improved firefighting apparatus configuration whereby the ball valve and relief valve are disposed behind the housing panel and between the panel and the pump.
Other objects and advantages of the present invention will be apparent from the following detailed description and appended claims, and upon reference to the accompanying drawings.